Many types of baby carriages and strollers have been developed to meet specific needs. For example, a perambulator style carriage was designed for "strolling" with a baby. Such a carriage is often suitable for only carrying an infant because no support is provided for carrying a child in a sitting position. Stroller style carriages have also been developed which can be configured either as an infant carriage for transporting a baby in a reclining position, or as a stroller for carrying a child in a sitting position. Such a carriage is shown in U.S. Pat. No. 4,836,573. In an effort to increase the utility of baby carriages, various collapsible frames were developed in order to make the carriages easier to store and transport. The carriages shown in the aforementioned U.S. Pat. No. 4,836,573 and in U.S. Pat. No. 4,606,550 are illustrative of such collapsible frames. However, the frame and wheel configuration of the aforementioned carriages are complicated to assemble and disassemble, and are not suitable for use on rough surfaces and uneven terrain, or at the faster speeds which might be associated with jogging or fitness-walking.
One attempt to solve the problem of making a carriage capable of traversing a rough surface or uneven terrain is to place the carriage onto a dolly having large surface bearing area wheels. A dolly having such a configuration is shown in U.S. Pat. No. 4,902,027. The major drawback of this solution is that two devices, a carriage and a dolly, must be used, thus increasing the difficulties associated with assembly, storage and transportation. An alternate solution is to provide a baby stroller having larger wheels, and a frame of more durable construction, thereby making the stroller suitable for traversing over a variety of terrain. Such a stroller is shown in U.S. Pat. No. 5,188,389. However, this stroller includes intricate coupler assemblies which must be disengaged in order for the stroller to be collapsed. Likewise, the frame tubes must be re-attached by the coupler assemblies in order to return this stroller to the upright configuration, so that the stroller cannot be returned to the upright operative position by the user through the use of one hand. Although the stroller of U.S. Pat. No. 5,188,389 collapses in height, the length of the frame is not reduced when collapsed, thus making it more difficult to store.
Accordingly, prior to the development of the present invention, no collapsible stroller existed which was capable of carrying either an infant or a toddler passenger, suitable for use over all types of terrain and ground surfaces, and transformable between a collapsed position of reduced height and length, and an upright position by the user through the use of one hand. A feature of the stroller of the present invention are releasable wheels which reduce its size and height for ease of storage and transportation. The advantages of the stroller of the present invention include its ability to carry passengers of both infant and toddler age, and its ability to be used for a variety of purposes, including shopping, recreation, jogging, or fitness-walking.